Mold



' ordinary course of factory 7 Patented Sept. 29; 1925.

UNITED STATES enoaen w. Bonner, or AKRON, omo, ASSIGNOR To run manna or AKRON, OHIO, a conrom'rron or 01:10.

PATENT OFFICE.

RUBBER COMPANY,

HOLD.

, Application filed November as, 1924. Serial in. venues.

To all whom it may com-em:

Be it known that I, Gnonen W. Bum nr, a citizen of the United States, and resident of Akron, in the county of Summ1t and State of Ohio, have-invented certain new and useful Improvements in Molds, of which the following is a specificatlon.

' The said invention relates particularly to molds such as are used for producing vul- 10 canized rubber articles;

These have gen- 'erally been made of cast iron or steel having the .mold cavity or cavities machined to give the proper smoothness, but whene the cavity is of irregular contour or intri- 15 cate design, this becomes an exceedingly 'diflicult and expensive 0 eration.

For such designs mo ds cast of a relativel soft metal have been used, but such mol shave not been satisfactory, as in the usage the soft metal is apt to be damage particularly at the edge or edges of the m under the heat and pressure of the molding 0 ration there is a tendency of the soft 5 meta to flow and produce a ridge or protuberance at the cavity edge with corresponding inequalities in the article.- The resentinvention aims to produce a mold w "ch may be economically and easily manufactured and which will be durable in use, and to this end it comprises the novel construction hereinafter described and defined by the appended claims.

A two-part mold embodying my invention is shown in the accompanying drawing,

in which Figure 1 is-a plan view of one of the mold members,

and

Fig. 2 is a transverse view through one of them, on line 2-2 of Fig. 1.

The mold shown is a two-part mold, each of the members of which comprises a main body portion 1 of relatively soft metal. and a facingplate 2 of hard metal such as steel, the exposed faces-ofthe two steel plates forming the parting line of the mold when the members are brought together. Each of the sections or members is shown as having a semiylindrical cavity designed to pro- 50 duce, when the m mbers are brou ht together to enclose t e rubber compound, a cylindrical mold chamber, but it will be understood that this is merely representative of any desired shape.

vents distortion' of, or

d cavity, and

whic

' It will also be understood that the mold members may be provided with the. usual dowel pins and openings for ensuring alignment of the members, but these are not shown herein, as forming no part ofthe invention;

It will also be understood that means may be provided for clamping the sections together, these not bein necessary in the mold shown, which is intended for press curing.

It will be observed that the hard metal or steel plate completely covers the parting face of each section and its inner edge coincides with and defines the edge of the mold cavity which,'being of hard metal, preinjury to the edge, as aforesaid.

A convenient manner of making each mold section is to provide a steel plate 2 of the desired size and shape having an opening of the proper outline cut therein, which plate would be placed upon a suport, bearing amatrix of a shape of onealf of the mold cavity, the matrix projecting throu h the opening.v Thereafter the soft meta mold body 1 would be cast about the matrix and upon the facing plate by the use of the usual molders flask. Preferably the steeliplate would be'provided with e soft metal together. escribed my lnvention,

knobs or headedrojections 3 which would be embedded in th a facing plate of r a mold soft metal permanently united to said plate and having a cavity, the edge of which is flilSh with the edge of the opening in said p ate.

3. A mold member comprising a body of relatively soft metal having a mold cavity,

and a hard metal facing plate completely covering the face of the member about said cavitiv, .said facin plate having projections Aare embed ed in the soft metal body.

4. two-part mold for vulcanizing rubber articles, comprising a pair of complesaid facing plate having an openin conmentary members having cooperating mold forming to the cavity in shape, the e ge of cavities, .each member comprising a body said opening defining the mouth of the mold 10 of relativel soft metal with a mold cavity cavity at the parting line.

'5 therein, an a hard metal faoin plate com- In testimony whereof, I aflix. my signapletely covering the soft meta body and ture. defining the parting line of the mold, the GEORGE W. BULLEY. 

